Cameron decries apparent beheading of Briton as 'pure evil'

The extremist group known as Islamic State released a video Saturday that purports to show the beheading of a British aid worker who was kidnapped in Syria near the Turkish border in March 2013.

The video, purporting to show the death of David Haines, 44, is similar to two others released in recent weeks that show the killing of the American journalists James Foley and Steven Sotloff. Britain’s Foreign and Commonwealth Office said it was working hard to verify the video’s authenticity.